OS 91 Surpass Engine Featured Engine: OS 91 Surpass

Four stroke engines tickle the fancy of many of us because they are simply “neat.” Their sound stirs the imagination, and they carry the airplane around the sky in a more realistic fashon. But they are expensive. A lot of money can be saved by buying used RC engines, if you can find a dependable used engine. I try to make all of my used engines relaible through repair, testing, and rating so you will know what you are getting before you buy.

BRAND SIZE RATING PRICE SKU DESCRIPTION
Magnum XL 70 7 $110 113  
Magnum XL 91 7 $130 115  
Magnum XL 91 8 $145 116 Has every bit as much “pinch” as an OS 91
Magnum XL 91 9 $155 114  
OS FL 70 6 $135 191 Tested with 13x6 prop. Ran at 9,500 rpm and idled at 2,100. Transition , compression, and bearings good.
OS Surpass 26 8 $130 166  
OS Surpass 48 7 $95 16  
OS Surpass 48 7 $100 17  
OS Surpass II 52 7 $125 164  
OS Surpass 70 7 $145 193  
OS Surpass 70 7- $135 198 Tested with 13x6 prop. Ran at 9,200 rpm and idled at 2,100. Compression, bearings, and transition good.
OS Surpass 91 7 $165 180  
OS Surpass 91 7 $170 178 Runs very well
OS Surpass 91 7+ $175 175 Tested with a wood 14x6 prop and got 9,750 high and 1,740 idle. Transition and bearings good.
OS Surpass 91 7 $170 196  
OS Surpass 91 7- $160 181 Tested with a 14x8 prop. Ran at 9,100 rpm and idled at 2,100. Transition, bearings, and compression good . New ring and needs to be run in.
OS Surpass 91 7- $160 199 Tested with 14x6 prop. Ran at 9450 rpm and idled at 2,100. Compression ,bearings, and transition good. Shows surface wear, but otherwise runs well.
OS surpass 91 9 $200 179 Bench run once for about 2 minutes.
OS Surpass II 91 8 $180 86  
Saito Gold Knight 50 6+ $100 161  
Saito 50 7 $110 158  
Saito 56 7 $130 159  
Saito 65 7 $140 160  
Saito 72 7 $155 177  
Saito 72 7 $150 165 Tested with a 13x7 prop and got 10,320 high and idled at 1,740. Compression, bearings and transition good.
Saito 72 8- $165 192  
Saito 80 7- $155 159 Tested with 13x7 prop. Ran at 10,290 and idled at 2,100. Bearings, transition and compression good.
Saito 80 7 $160 163  
Saito 91 6 $130 155 Tested with a 14x6 prop. Ran at 9360 rpm and idled at 2,200. Plug the extra hole in the muffler and I think the idle wil be reduced. Bearings, transition, and compression are good.
Saito 91 7+ $175 185  
Saito 91 8- $180 200 Tested with 14x6 prop RAN at 9,360 rpm and idoled at 1,860. Compression, bearings, and transition good. Impressive.
Saito 91 8 $185 148  
Saito 91 8 $180 154 Muffler older than engine.
Saito 100 7 $180 172  
Saito 100 7+ $190 167 Runs fantastically well. tested with a 14x8 prop and got 9,000 rpm on high and idled at 1,800 rpm.
Saito 100 8 $200 195  
Saito 120 7 $190 229 Tested with 16x8 prop. Ran at 7,400 rpm and idled at 1,700. Will get 1,000 rpm more with a 16x6 prop. Transition, compression and bearings good.
Saito 120 7 $200 228 Tested with 16x8 prop. Ran at 7,920 rpm and idled at 1,700. Will get 1,000 rpm more with a 16x6 prop. Transition, compression, and bearings good.
Saito 120S 6 $170 227 Tested with 16x8 prop. Ran at 7,830 rpm and idled at 1,800. Will get 1,000 rpm more with a 16x6 prop. Transition, compression and bearings good. Carb will not tighten firm. Add fitted nut to firm it up.
YS FZ 53 6 $125 157  
YS FZ 91 7 $175 162 Impressive engine.
YS AC 110 8 $200 170  
YS AC 120 7 $195 238  
YS FS 120 7 $200 243 Stack Exhaust
YS SF 120 7 $210 244 Bulb muffler
YS SF 120 8 $215 246  
YS SF 120 7 $205 205 Muffler and 45 degree header
YS FS 120 7+ $210 239  
YS NC 120 7 $205 237 90 header plus a muffler